1. Field of the Invention
The present invention relates to a molding condition recording apparatus for an injection molding machine, capable of recording one or more histories of processes for determining optimum molding conditions. Using the present invention, optimum molding conditions are determined with plural sets of molding conditions which are individually set. If the result of a process is successful, the conditions which precipitated the result can be duplicated using the history of the conditions recorded by the present invention. Conversely, if the result of certain molding conditions is defective, the conditions which precipitated the result can be avoided using the history of conditions recorded by the present invention.
2. Description of Related Art
Molding conditions for carrying out an injection molding process including a series of steps, such as an injection, hold, metering, etc., involve various parameters. Accordingly, the optimum molding conditions for manufacturing non-defective molded products are generally determined through trial and error. More specifically, the injection molding process is carried out in accordance with tentatively set molding conditions. After inspection of the resulting molded product, one or more parameters of the molding conditions are changed according to the quality of molded products obtained. The injection molding process is again carried out with the modified molding conditions. This procedure is repeated to obtain the optimum molding conditions. The optimum molding conditions determined in this manner are stored in a recording apparatus of an injection molding machine, so that the injection molding process is carried out in accordance with the stored optimum molding conditions.
It is known, for example, from Japanese Patent Disclosure No. 61-114831, that molding conditions can be stored in a mold data table corresponding to mold numbers. According to this prior art, when a mold number representing a particular mold is designated before the execution of the injection molding process, optimum molding conditions for this mold are displayed. It is also known that the optimum molding conditions can be stored in a setting memory, and then written into a molding condition file memory correspondingly to mold types (Japanese Patent Disclosure No. 61-248722). In this prior art, the optimum molding conditions for a mold type to be used are transferred from the molding condition file memory to the setting memory, and the injection molding process is carried out in accordance with the optimum molding conditions stored in the setting memory. It is also known that the optimum molding conditions stored in the aforesaid manner can be printed out (Japanese Patent Disclosure No. 62-261418).
As described, the prior art apparatuses are designed to store or print only the optimum molding conditions. Accordingly, when determining or correcting optimum molding conditions because of defective molding produced by the injection molding process in accordance with once-determined optimum molding conditions the injection molding process should be repeated while parameters of the molding conditions are changed many times. It is, however, difficult to grasp entire processes of changing the molding conditions involving numerous parameters, and therefore, it frequently happens that molding conditions similar to those which were already tested and found to produce defective molding are inadvertently used to carry out the injection molding process which leads to a waste of time.